I just bought a 2012 chevy silverado 2500hd with the 6.0, 3.73 rear end and the six speed auto.

I towed my 7000 lb toy hauler for the first time this weekend and was mostly satisfied with the performance.

However I am not impressed much like others with how the transmission selects gears. On the flat interstate of eastern VA and NC I would like it to hold 5th gear longer before downshifting. The engine makes plenty of torque with a wider throttle opening to pull small hills in 5th at this weight but it won't let me. It wants to drop to 4th or 3rd and run 4k rpm at 65 instead of the 2400 in 5th.

What do you guys reccomend as far as getting this fixed without voiding the warranty.

What I really want is a retune that turns manual mode into a true manual mode. If I put it in 5th or 4th or whatever gear it stays there no matter what. Instead of gm's version of manual mode which is just an overdrive lockout.

Taco wrote:What I really want is a retune that turns manual mode into a true manual mode. If I put it in 5th or 4th or whatever gear it stays there no matter what. Instead of gm's version of manual mode which is just an overdrive lockout.

Taco wrote:What I really want is a retune that turns manual mode into a true manual mode. If I put it in 5th or 4th or whatever gear it stays there no matter what. Instead of gm's version of manual mode which is just an overdrive lockout.

The computer in your truck is programmed to maximize the power in the engine. As previously suggested, the best thing for you to do, is to put the transmission in drive, switch on Tow/Haul and let the computers do their job. Doing that, you safely maximize engine and transmission performance and fuel economy. Adding a chip would void your warranty, overstress your engine and transmission and reduce your fuel ecomomy.
While I have a diesel, I've decided to not second guess the GM engineers who designed the engine, so my engine is bone stock.

Never heard of anything out there that can change that for you. Selling it is not always the answere either. Just follow the guide on using tow haul and let the computer do its job. The truck will have no difficulty pulling that little of wieght. Going to 4K may feak some out. I would prefer to have it at 4K instead of lugging it causing damage to the drive train. At 4K that engine is not working hard at all, it's all about perception.

A truck, a camper, a few toys, but most importantly a wonderful family.

Only 2nd gear works that way. Other gears in manual mode are just range limiting, as in it will not shift above the selected gear, but will shift below according to the regular or tow/haul mode shift patterns.

Tow/Haul and Manual 5 are what I use. They do a good job most of the time. Not sure what the problem is with 4000rpm from the 6.0L. Sounds good to my ears.

Even if a tuner could lock a gear, I doubt the driver would be happy. The transmission shifts down a gear (or more) because the engine knows there is not enough torque at the current engine speed to meet driver's demand.

About all you can do is use tow/haul and manual mode to select the gear that minimizes gear hunting and lugging. So, sounds like 4 in your case. Really, the extra RPM's don't hurt the engine a bit, and you're doing the best thing for the truck. I towed in 3rd gear most of the time with all of my old gas engines - before manual mode came out - and everything always turned out just fine. Turn up the tunes a bit and forget about it.....